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- /*
- * Primitives for displaying the file on the screen.
- */
-
- #include "less.h"
- #include "position.h"
-
- public int hit_eof; /* Keeps track of how many times we hit end of file */
- public int screen_trashed;
-
- static int squished;
-
- extern int quiet;
- extern int sigs;
- extern int how_search;
- extern int top_scroll;
- extern int back_scroll;
- extern int sc_width, sc_height;
- extern int quit_at_eof;
- extern int caseless;
- extern int linenums;
- extern int plusoption;
- extern char *line;
- extern char *first_cmd;
- #if TAGS
- extern int tagoption;
- #endif
-
- /*
- * Sound the bell to indicate he is trying to move past end of file.
- */
- static void
- eof_bell()
- {
- if (quiet == NOT_QUIET)
- bell();
- else
- vbell();
- }
-
- /*
- * Check to see if the end of file is currently "displayed".
- */
- static void
- eof_check()
- {
- POSITION pos;
-
- if (sigs)
- return;
- /*
- * If the bottom line is empty, we are at EOF.
- * If the bottom line ends at the file length,
- * we must be just at EOF.
- */
- pos = position(BOTTOM_PLUS_ONE);
- if (pos == NULL_POSITION || pos == ch_length())
- hit_eof++;
- }
-
- /*
- * If the screen is "squished", repaint it.
- * "Squished" means the first displayed line is not at the top
- * of the screen; this can happen when we display a short file
- * for the first time.
- */
- static void
- squish_check()
- {
- if (!squished)
- return;
- squished = 0;
- repaint();
- }
-
- /*
- * Display n lines, scrolling forward,
- * starting at position pos in the input file.
- * "force" means display the n lines even if we hit end of file.
- * "only_last" means display only the last screenful if n > screen size.
- */
- static void
- forw(n, pos, force, only_last)
- register int n;
- POSITION pos;
- int force;
- int only_last;
- {
- int eof = 0;
- int nlines = 0;
- int do_repaint;
- static int first_time = 1;
-
- squish_check();
-
- /*
- * do_repaint tells us not to display anything till the end,
- * then just repaint the entire screen.
- */
- do_repaint = (only_last && n > sc_height-1);
-
- if (!do_repaint)
- {
- if (top_scroll && n >= sc_height - 1)
- {
- /*
- * Start a new screen.
- * {{ This is not really desirable if we happen
- * to hit eof in the middle of this screen,
- * but we don't yet know if that will happen. }}
- */
- if (top_scroll == 2)
- clear();
- home();
- force = 1;
- } else
- {
- lower_left();
- clear_eol();
- }
-
- if (pos != position(BOTTOM_PLUS_ONE))
- {
- /*
- * This is not contiguous with what is
- * currently displayed. Clear the screen image
- * (position table) and start a new screen.
- */
- pos_clear();
- add_forw_pos(pos);
- force = 1;
- if (top_scroll)
- {
- if (top_scroll == 2)
- clear();
- home();
- } else if (!first_time)
- {
- putstr("...skipping...\n");
- }
- }
- }
-
- while (--n >= 0)
- {
- /*
- * Read the next line of input.
- */
- pos = forw_line(pos);
- if (pos == NULL_POSITION)
- {
- /*
- * End of file: stop here unless the top line
- * is still empty, or "force" is true.
- */
- eof = 1;
- if (!force && position(TOP) != NULL_POSITION)
- break;
- line = NULL;
- }
- /*
- * Add the position of the next line to the position table.
- * Display the current line on the screen.
- */
- add_forw_pos(pos);
- nlines++;
- if (do_repaint)
- continue;
- /*
- * If this is the first screen displayed and
- * we hit an early EOF (i.e. before the requested
- * number of lines), we "squish" the display down
- * at the bottom of the screen.
- * But don't do this if a + option or a -t option
- * was given. These options can cause us to
- * start the display after the beginning of the file,
- * and it is not appropriate to squish in that case.
- */
- if (first_time && line == NULL && !top_scroll &&
- #if TAGS
- !tagoption &&
- #endif
- !plusoption)
- {
- squished = 1;
- continue;
- }
- if (top_scroll == 1)
- clear_eol();
- put_line();
- }
-
- if (eof && !sigs)
- hit_eof++;
- else
- eof_check();
- if (nlines == 0)
- eof_bell();
- else if (do_repaint)
- repaint();
- first_time = 0;
- (void) currline(BOTTOM);
- }
-
- /*
- * Display n lines, scrolling backward.
- */
- static void
- back(n, pos, force, only_last)
- register int n;
- POSITION pos;
- int force;
- int only_last;
- {
- int nlines = 0;
- int do_repaint;
-
- squish_check();
- do_repaint = (n > get_back_scroll() || (only_last && n > sc_height-1));
- hit_eof = 0;
- while (--n >= 0)
- {
- /*
- * Get the previous line of input.
- */
- pos = back_line(pos);
- if (pos == NULL_POSITION)
- {
- /*
- * Beginning of file: stop here unless "force" is true.
- */
- if (!force)
- break;
- line = NULL;
- }
- /*
- * Add the position of the previous line to the position table.
- * Display the line on the screen.
- */
- add_back_pos(pos);
- nlines++;
- if (!do_repaint)
- {
- home();
- add_line();
- put_line();
- }
- }
-
- eof_check();
- if (nlines == 0)
- eof_bell();
- else if (do_repaint)
- repaint();
- (void) currline(BOTTOM);
- }
-
- /*
- * Display n more lines, forward.
- * Start just after the line currently displayed at the bottom of the screen.
- */
- public void
- forward(n, only_last)
- int n;
- int only_last;
- {
- POSITION pos;
-
- if (quit_at_eof && hit_eof)
- {
- /*
- * If the -e flag is set and we're trying to go
- * forward from end-of-file, go on to the next file.
- */
- next_file(1);
- return;
- }
-
- pos = position(BOTTOM_PLUS_ONE);
- if (pos == NULL_POSITION)
- {
- eof_bell();
- hit_eof++;
- return;
- }
- forw(n, pos, 0, only_last);
- }
-
- /*
- * Display n more lines, backward.
- * Start just before the line currently displayed at the top of the screen.
- */
- public void
- backward(n, only_last)
- int n;
- int only_last;
- {
- POSITION pos;
-
- pos = position(TOP);
- if (pos == NULL_POSITION)
- {
- /*
- * This will almost never happen,
- * because the top line is almost never empty.
- */
- eof_bell();
- return;
- }
- back(n, pos, 0, only_last);
- }
-
- /*
- * Repaint the screen, starting from a specified position.
- */
- static void
- prepaint(pos)
- POSITION pos;
- {
- hit_eof = 0;
- forw(sc_height-1, pos, 1, 0);
- screen_trashed = 0;
- }
-
- /*
- * Repaint the screen.
- */
- public void
- repaint()
- {
- /*
- * Start at the line currently at the top of the screen
- * and redisplay the screen.
- */
- prepaint(position(TOP));
- }
-
- /*
- * Jump to the end of the file.
- * It is more convenient to paint the screen backward,
- * from the end of the file toward the beginning.
- */
- public void
- jump_forw()
- {
- POSITION pos;
-
- if (ch_end_seek())
- {
- error("Cannot seek to end of file");
- return;
- }
- lastmark();
- pos = ch_tell();
- clear();
- pos_clear();
- add_back_pos(pos);
- back(sc_height - 1, pos, 0, 0);
- }
-
- /*
- * Jump to line n in the file.
- */
- public void
- jump_back(n)
- register int n;
- {
- register int c;
- int nlines;
-
- /*
- * This is done the slow way, by starting at the beginning
- * of the file and counting newlines.
- *
- * {{ Now that we have line numbering (in linenum.c),
- * we could improve on this by starting at the
- * nearest known line rather than at the beginning. }}
- */
- if (ch_seek((POSITION)0))
- {
- /*
- * Probably a pipe with beginning of file no longer buffered.
- * If he wants to go to line 1, we do the best we can,
- * by going to the first line which is still buffered.
- */
- if (n <= 1 && ch_beg_seek() == 0)
- jump_loc(ch_tell());
- error("Cannot get to beginning of file");
- return;
- }
-
- /*
- * Start counting lines.
- */
- for (nlines = 1; nlines < n; nlines++)
- {
- while ((c = ch_forw_get()) != '\n')
- if (c == EOI)
- {
- char message[40];
- sprintf(message, "File has only %d lines",
- nlines-1);
- error(message);
- return;
- }
- }
-
- jump_loc(ch_tell());
- }
-
- /*
- * Jump to a specified percentage into the file.
- * This is a poor compensation for not being able to
- * quickly jump to a specific line number.
- */
- public void
- jump_percent(percent)
- int percent;
- {
- POSITION pos, len;
- register int c;
-
- /*
- * Determine the position in the file
- * (the specified percentage of the file's length).
- */
- if ((len = ch_length()) == NULL_POSITION)
- {
- error("Don't know length of file");
- return;
- }
- pos = (percent * len) / 100;
-
- /*
- * Back up to the beginning of the line.
- */
- if (ch_seek(pos) == 0)
- {
- while ((c = ch_back_get()) != '\n' && c != EOI)
- ;
- if (c == '\n')
- (void) ch_forw_get();
- pos = ch_tell();
- }
- jump_loc(pos);
- }
-
- /*
- * Jump to a specified position in the file.
- */
- public void
- jump_loc(pos)
- POSITION pos;
- {
- register int nline;
- POSITION tpos;
-
- if ((nline = onscreen(pos)) >= 0)
- {
- /*
- * The line is currently displayed.
- * Just scroll there.
- */
- forw(nline, position(BOTTOM_PLUS_ONE), 1, 0);
- return;
- }
-
- /*
- * Line is not on screen.
- * Seek to the desired location.
- */
- if (ch_seek(pos))
- {
- error("Cannot seek to that position");
- return;
- }
-
- /*
- * See if the desired line is BEFORE the currently
- * displayed screen. If so, then move forward far
- * enough so the line we're on will be at the bottom
- * of the screen, in order to be able to call back()
- * to make the screen scroll backwards & put the line
- * at the top of the screen.
- * {{ This seems inefficient, but it's not so bad,
- * since we can never move forward more than a
- * screenful before we stop to redraw the screen. }}
- */
- tpos = position(TOP);
- if (tpos != NULL_POSITION && pos < tpos)
- {
- POSITION npos = pos;
- /*
- * Note that we can't forw_line() past tpos here,
- * so there should be no EOI at this stage.
- */
- for (nline = 0; npos < tpos && nline < sc_height - 1; nline++)
- npos = forw_line(npos);
-
- if (npos < tpos)
- {
- /*
- * More than a screenful back.
- */
- lastmark();
- clear();
- pos_clear();
- add_back_pos(npos);
- }
-
- /*
- * Note that back() will repaint() if nline > back_scroll.
- */
- back(nline, npos, 1, 0);
- return;
- }
- /*
- * Remember where we were; clear and paint the screen.
- */
- lastmark();
- prepaint(pos);
- }
-
- /*
- * The table of marks.
- * A mark is simply a position in the file.
- */
- #define NMARKS (27) /* 26 for a-z plus one for quote */
- #define LASTMARK (NMARKS-1) /* For quote */
- static POSITION marks[NMARKS];
-
- /*
- * Initialize the mark table to show no marks are set.
- */
- public void
- init_mark()
- {
- int i;
-
- for (i = 0; i < NMARKS; i++)
- marks[i] = NULL_POSITION;
- }
-
- /*
- * See if a mark letter is valid (between a and z).
- */
- static int
- badmark(c)
- int c;
- {
- if (c < 'a' || c > 'z')
- {
- error("Choose a letter between 'a' and 'z'");
- return (1);
- }
- return (0);
- }
-
- /*
- * Set a mark.
- */
- public void
- setmark(c)
- int c;
- {
- if (badmark(c))
- return;
- marks[c-'a'] = position(TOP);
- }
-
- public void
- lastmark()
- {
- marks[LASTMARK] = position(TOP);
- }
-
- /*
- * Go to a previously set mark.
- */
- public void
- gomark(c)
- int c;
- {
- POSITION pos;
-
- if (c == '\'')
- pos = marks[LASTMARK];
- else if (badmark(c))
- return;
- else
- pos = marks[c-'a'];
-
- if (pos == NULL_POSITION)
- error("mark not set");
- else
- jump_loc(pos);
- }
-
- /*
- * Get the backwards scroll limit.
- * Must call this function instead of just using the value of
- * back_scroll, because the default case depends on sc_height and
- * top_scroll, as well as back_scroll.
- */
- public int
- get_back_scroll()
- {
- if (back_scroll >= 0)
- return (back_scroll);
- if (top_scroll)
- return (sc_height - 2);
- return (sc_height - 1);
- }
-
- /*
- * Search for the n-th occurence of a specified pattern,
- * either forward or backward.
- */
- public void
- search(search_forward, pattern, n, wantmatch)
- register int search_forward;
- register char *pattern;
- register int n;
- int wantmatch;
- {
- POSITION pos, linepos;
- register char *p;
- register char *q;
- int linenum;
- int linematch;
- #if RECOMP
- char *re_comp();
- char *errmsg;
- #else
- #if REGCMP
- char *regcmp();
- static char *cpattern = NULL;
- #else
- static char lpbuf[100];
- static char *last_pattern = NULL;
- #endif
- #endif
-
- if (caseless && pattern != NULL)
- {
- /*
- * For a caseless search, convert any uppercase
- * in the pattern to lowercase.
- */
- for (p = pattern; *p != '\0'; p++)
- if (*p >= 'A' && *p <= 'Z')
- *p += 'a' - 'A';
- }
- #if RECOMP
-
- /*
- * (re_comp handles a null pattern internally,
- * so there is no need to check for a null pattern here.)
- */
- if ((errmsg = re_comp(pattern)) != NULL)
- {
- error(errmsg);
- return;
- }
- #else
- #if REGCMP
- if (pattern == NULL || *pattern == '\0')
- {
- /*
- * A null pattern means use the previous pattern.
- * The compiled previous pattern is in cpattern, so just use it.
- */
- if (cpattern == NULL)
- {
- error("No previous regular expression");
- return;
- }
- } else
- {
- /*
- * Otherwise compile the given pattern.
- */
- char *s;
- if ((s = regcmp(pattern, 0)) == NULL)
- {
- error("Invalid pattern");
- return;
- }
- if (cpattern != NULL)
- free(cpattern);
- cpattern = s;
- }
- #else
- if (pattern == NULL || *pattern == '\0')
- {
- /*
- * Null pattern means use the previous pattern.
- */
- if (last_pattern == NULL)
- {
- error("No previous regular expression");
- return;
- }
- pattern = last_pattern;
- } else
- {
- strcpy(lpbuf, pattern);
- last_pattern = lpbuf;
- }
- #endif
- #endif
-
- /*
- * Figure out where to start the search.
- */
-
- if (position(TOP) == NULL_POSITION)
- {
- /*
- * Nothing is currently displayed.
- * Start at the beginning of the file.
- * (This case is mainly for first_cmd searches,
- * for example, "+/xyz" on the command line.)
- */
- pos = (POSITION)0;
- } else if (!search_forward)
- {
- /*
- * Backward search: start just before the top line
- * displayed on the screen.
- */
- pos = position(TOP);
- } else if (how_search == 0)
- {
- /*
- * Start at the second real line displayed on the screen.
- */
- pos = position(TOP);
- do
- pos = forw_raw_line(pos);
- while (pos < position(TOP+1));
- } else if (how_search == 1)
- {
- /*
- * Start just after the bottom line displayed on the screen.
- */
- pos = position(BOTTOM_PLUS_ONE);
- } else
- {
- /*
- * Start at the second screen line displayed on the screen.
- */
- pos = position(TOP_PLUS_ONE);
- }
-
- if (pos == NULL_POSITION)
- {
- /*
- * Can't find anyplace to start searching from.
- */
- error("Nothing to search");
- return;
- }
-
- linenum = find_linenum(pos);
- for (;;)
- {
- /*
- * Get lines until we find a matching one or
- * until we hit end-of-file (or beginning-of-file
- * if we're going backwards).
- */
- if (sigs)
- /*
- * A signal aborts the search.
- */
- return;
-
- if (search_forward)
- {
- /*
- * Read the next line, and save the
- * starting position of that line in linepos.
- */
- linepos = pos;
- pos = forw_raw_line(pos);
- if (linenum != 0)
- linenum++;
- } else
- {
- /*
- * Read the previous line and save the
- * starting position of that line in linepos.
- */
- pos = back_raw_line(pos);
- linepos = pos;
- if (linenum != 0)
- linenum--;
- }
-
- if (pos == NULL_POSITION)
- {
- /*
- * We hit EOF/BOF without a match.
- */
- error("Pattern not found");
- return;
- }
-
- /*
- * If we're using line numbers, we might as well
- * remember the information we have now (the position
- * and line number of the current line).
- */
- if (linenums)
- add_lnum(linenum, pos);
-
- if (caseless)
- {
- /*
- * If this is a caseless search, convert
- * uppercase in the input line to lowercase.
- * While we're at it, remove any backspaces
- * along with the preceeding char.
- * This allows us to match text which is
- * underlined or overstruck.
- */
- for (p = q = line; *p != '\0'; p++, q++)
- {
- if (*p >= 'A' && *p <= 'Z')
- /* Convert uppercase to lowercase. */
- *q = *p + 'a' - 'A';
- else if (q > line && *p == '\b')
- /* Delete BS and preceeding char. */
- q -= 2;
- else
- /* Otherwise, just copy. */
- *q = *p;
- }
- }
-
- /*
- * Test the next line to see if we have a match.
- * This is done in a variety of ways, depending
- * on what pattern matching functions are available.
- */
- #if REGCMP
- linematch = (regex(cpattern, line) != NULL);
- #else
- #if RECOMP
- linematch = (re_exec(line) == 1);
- #else
- linematch = match(pattern, line);
- #endif
- #endif
- /*
- * We are successful if wantmatch and linematch are
- * both true (want a match and got it),
- * or both false (want a non-match and got it).
- */
- if (((wantmatch && linematch) || (!wantmatch && !linematch)) &&
- --n <= 0)
- /*
- * Found the line.
- */
- break;
- }
-
- jump_loc(linepos);
- }
-
- #if (!REGCMP) && (!RECOMP)
- /*
- * We have neither regcmp() nor re_comp().
- * We use this function to do simple pattern matching.
- * It supports no metacharacters like *, etc.
- */
- static int
- match(pattern, buf)
- char *pattern, *buf;
- {
- register char *pp, *lp;
-
- for ( ; *buf != '\0'; buf++)
- {
- for (pp = pattern, lp = buf; *pp == *lp; pp++, lp++)
- if (*pp == '\0' || *lp == '\0')
- break;
- if (*pp == '\0')
- return (1);
- }
- return (0);
- }
- #endif
-